Across the Tracks
by mabel-but-slytherin
Summary: Dipper and Mabel Pines are determined to discover the secrets of their summer home in Gravity Falls Wyoming, the most mysterious of which being that of the old railroad tracks surrounding town that no one dares to cross. Could the origin of Gravity Falls be tied to its founder? And what of those plotting its destruction from the outside?


**AN: Alright, time for another Superfalls AU! Because I totally don't have enough of those going around! This idea is probably going to be largely built up in chapters of this story, and early on will likely be retellings of relevant episodes that have changed given the AU.**

**The idea is inspired by someone asking about how Gravity Falls came to house the supernatural menagerie it does. In this AU that's answered more by changing the location of where Gravity Falls is.**

**Enjoy!**

* * *

Hello, my name is Dipper Pines. The girl screaming in the passenger seat of our golf cart is my sister Mabel. Today's the day when everything changed.

It all started as we were running (or more accurately, golf-carting) for our lives from a monster made of a thousand angry gnomes all trying to marry my sister. I know what you're wondering, have our lives always been this weird?

The answer is no, it all started when our parents sent us to spend the summer with our Great Uncle Stan in Gravity Falls, Wyoming.

"Dipper! Make this thing go faster! They're gaining on us!" Oh, right, back to focusing on the road and trying to outrun the giant monster that's tearing apart the woods behind us.

"I can't! It's just a golf cart!" The monster begins firing off gnomes as projectiles, one landing on the golf cart that promptly began clawing my face until Mabel punched it, sending it flying as the cart sped on.

"Hey, look! Signs for the Shack, we're almost there!" I would know, I spent all morning nailing the advertisements in the forest before finding the journal that led me to suspect my sister's boyfriend of being a supernatural creature. It's a great story, but one that can wait until it's actually over.

"We're gonna make it, we're gonna make it!" And just our luck, as soon as Mabel began shouting with her unrelenting optimism, fate had to come along and jinx it in the form of a well-thrown tree flying over our heads, ominously shadowing the sky as it threatened to crush us. Doing the only thing I could think of while panicking behind the wheel, I let my instincts take over and swerved the cart at a ninety degree angle before continuing to put the pedal to the metal to keep the chase going.

"Dipper, what are you doing?! The Shack's back that way!" Mabel pointed frantically in the direction we came from. The gnomes, smart enough to realize that was our original destination, quickly moved to block the path back, cutting off our escape while buying us a little more distance.

"Mabel, sweetie, there's no way back but through us! Just turn around and marry us now before someone gets hurt!"

"I'll never marry you Jeff! You're all just a bunch of creepy buttfaces!" Mabel turns from yelling at them to smile sweetly at me, "hit it, bro-bro."

"You got it."

Guess that leaves moving forward as our only option. We take the path deeper and deeper into the woods, driving away from the Shack and in the opposite direction of town. The forest gets darker as we go along, and quickly any attempts at conversation are drowned out by my focus on the narrowing road (if the unpaved hiking trail can even be called that) and Mabel's screams as we bounce over rocks, branches, and uneven terrain.

Luckily, the thickening forestry slows down our pursuers as much as it does the golf cart, and we seem to reach a stalemate in terms of distance gained and lost. Once I get the hang of navigating the path before me, I realize that I could do this all day, before noticing that the darkening sky is as much from the passing of the afternoon as from the deepening of the forest. Mabel appears to have similar thoughts, as her eyes dart to meet mine with a whole new kind of fear, before turning back to the trail and settling on the dashboard.

"Oh no, Dipper, the fuel gauge!"

My eyes follow where her finger's pointing to verify that indeed the arrow is pointing dangerously close to empty. My mind wanders to try to think of a solution, when suddenly we bounce over a giant obstacle neither of us noticed in the way, completely flipping the golf cart onto its side.

We both unbuckle ourselves and slowly climb out and I'm suddenly really glad I made sure Mabel buckled her seatbelt. I turn my head towards her to see her rubbing her own head muttering as she crawls forward to investigate.

"Oww, what hit us…?" Directly behind the golf cart was two ridges a couple of inches tall passing straight through the forest perpendicular to the direction we were going in. They must be old, if the weeds and roots growing over it and hiding it from sight were anything to go by. But they also maintained their distinctive shape after all these years, which meant that they were sturdy. And they continued on into the forest in both directions, forming a small break in some of the taller trees around them as if the forest had once been cut there when they were made…

"Mabel, I think these are railroad tracks!" Yep, now that I had identified what they were, I could look closely and see the rusted nails holding them down and old planks of wood keeping the tracks together.

"Whoa… but what are railroad tracks like these doing in the middle of nowhere by Gravity Falls?" Mabel seemed to stare at them in wonder, before moving the rest of the way towards them and rubbing her hands along the old metal. I quickly pulled her back, don't want her catching tetanus or something bad like that.

"We knew you'd have to stop running eventually! Now just come with us peacefully and be our queen!" Oh no, I completely forgot about the gnomes. Looking over at Mabel's shocked and horrified expression as she stared up at the approaching gnomes I realized that she made the same mistake as well.

The giant creature came to a stop about ten feet from us, and I could just barely make out Jeff at the very top of the gnomes smiling triumphantly down at us. "Welp, time to claim my bride. Let me down, will you guys?" He began climbing down all of the gnomes as the twisted and turned in place, before one in the middle of the thigh area's eyes landed on the tracks in front of Mabel and seemed to completely freeze in fear.

"Oh no, the tracks! They're on the other side of the tracks!"

All at once the gnomes burst into chaos, kicking and squirming and flailing as Jeff quickly changed his direction and scampered back to his place at the head, all as the mass took off in a sprint in the opposite direction. "You may have gotten away from us now, but you'll have to cross back over sometime! We'll be waiting in the forest for you Mabel! The gnomes are a powerful race, and we'll have our queen eventually!" A few seconds and many screams of terror later, all of the gnomes were gone.

Mabel instantly perked up and began wiping dirt off of her skirt. "Well, that was weird."

"Tell me about it. But I don't get it, why were the gnomes so terrified as soon as they saw the railroad tracks? They chased us for miles and we were right here, but they wouldn't even come get us and ran away as fast as they could."

"I don't know, but I for one am grateful. I want the perfect summer romance, and while proposing is sweet, trying to force a girl into marriage before the first date! Ick."

"Ick is right." I take a second to look around, trying to figure out why I suddenly feel like I'm being watched, even though there's nothing around, not even the sounds of any wildlife one would expect this deep in the woods. "There's certainly something ominous about this place…"

I felt a tap on my shoulder and turned around screaming, just to see Mabel behind me with her hand still raised in a shoulder bump. She promptly burst out laughing.

"Let's just go home." Together we pushed and finally righted the golf cart, checking to make sure it wasn't too damaged before putting the keys in the ignition and heading off on our way. We might not have enough fuel to make it all the way back, but it's getting late and it's best to get the cart as close to the Shack as possible.

"That place was definitely creepy. We should go camping there sometime!" That's my sister, ever the optimist.

* * *

Grunkle Stan barely looked up from counting his money as we walked down from the attic that evening. I couldn't help but pause and stare at him because honestly, wasn't he just counting his money when we walked back into the gift shop?

"So, uh, how are those presents working out?" I look up at my new hat and smile, noting again the odd way I feel more complete with it sitting on top of my head.

"GRAPPLING HOOK!" And there goes Mabel, trying to swing over my head where I've paused on the stairs and into the living room with her newfound favorite possession. She winds up crashing into the wall.

I would be more concerned if this wasn't so typical.

"Yeesh. This is going to be quite the summer watching you two." Grunkle Stan, as usual, managed to add not an ounce of either question or concern to that statement. "What were you kids doing out all day anyway? You come back after the shop closed beat up and practically pushing the golf cart. If you keep skipping work and breaking things I might actually need to hire another employee!"

I can't help but sigh, of course that's what he'd be concerned about. "We were just out exploring in the forest."

"Yeah! And we found a really cool set of old railroad tracks!"

"WHAT?!" Grunkle Stan suddenly sat up ramrod straight from where he had been leaning back in his chair at the table, spit-taking Pitt Cola all the way across the room.

"Yeah," I reply, maybe taking a little too much pride in seeing Grunkle Stan so shocked. "We were driving the golf cart through the woods when we found some railroad tracks going by. I never knew there were trains near Gravity Falls."

"They're all around the edge of town kid, you must've drove over them on the bus when you were on your way here." Grunkle Stan paused from getting up to get himself another glass of soda when he turned to face us. "Now listen to me kids. I may not be the strictest guardian, but there's one rule I want you two to follow while you're here. Stay away from those tracks, and whatever you do, don't cross over to the other side unless you have me driving you someplace. You got it?"

"But why, Grunkle Stan? They're just a bunch of old railroad tracks."

"They're far from the Shack, that's why. Can't have you two wandering off in the middle of nowhere where no one can find you." He turned away at that point, and something in his voice made me wonder if there was more to it than that.

"So then why the railroad tracks in particular? Why not just tell us we can't go play in the miles of uninhabited forest leading up to that point?"

"Do you want me to ground you kids to the Shack?" He turned to check as we both quickly shook our heads no. "I'm just picking that spot because it's a good landmark. Neither of you are ever to go within sight of that thing. See, clear, understandable boundaries. All that good responsible moral guardian stuff." I glanced at Mabel and had to cover a chuckle, because Stan's _totally_ the prime example of the perfect role model.

"Kids! Why is there Diet Pitt Cola in the fridge? I thought I told you to steal the good stuff!"

It was certainly going to be an interesting summer.

* * *

**One last hint: if you haven't realized where Gravity Falls is and how this ties into Supernatural, check out the story image *winks***

**Feel free to review or pm me with questions! I don't have that many ideas for this universe so I'd love to have some conversations/inspirations/see what other people can do with it!**


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